I just recentered IM4, by moving the picomotor +400 counts in the X direction and +4100 counts in the Y direction.

The QPD started at -0.47 PIT and 0.12 YAW, now both are fluctuating around 0.

model restarts logged for Wed 21/Sep/2016
2016_09_21 10:24 h1fw1
2016_09_21 10:47 h1calcs
2016_09_21 18:18 h1nds0
2016_09_21 20:36 h1fw0
2016_09_21 21:24 h1fw0

return of fw1 after cloning work was abandoned. Jeff and Darkhan's calcs C code change (no daq restart). Unexpected restart of h1nds0, continuing fw0 instability.

model restarts logged for Tue 20/Sep/2016
2016_09_20 13:37 h1psliss
2016_09_20 13:43 h1broadcast0
2016_09_20 13:43 h1dc0
2016_09_20 13:43 h1fw0
2016_09_20 13:43 h1fw2
2016_09_20 13:43 h1nds0
2016_09_20 13:43 h1nds1
2016_09_20 13:43 h1tw0
2016_09_20 13:43 h1tw1
2016_09_20 13:53 h1susprocpi
2016_09_20 13:55 h1broadcast0
2016_09_20 13:55 h1dc0
2016_09_20 13:55 h1fw0
2016_09_20 13:55 h1fw2
2016_09_20 13:55 h1nds0
2016_09_20 13:55 h1nds1
2016_09_20 13:55 h1tw0
2016_09_20 13:55 h1tw1
2016_09_20 14:48 h1psliss
2016_09_20 14:50 h1broadcast0
2016_09_20 14:50 h1dc0
2016_09_20 14:50 h1fw0
2016_09_20 14:50 h1fw2
2016_09_20 14:50 h1nds0
2016_09_20 14:50 h1nds1
2016_09_20 14:50 h1tw0
2016_09_20 14:50 h1tw1
2016_09_20 15:18 h1psliss
2016_09_20 17:05 h1calcs
2016_09_20 17:06 h1broadcast0
2016_09_20 17:06 h1dc0
2016_09_20 17:06 h1fw0
2016_09_20 17:06 h1fw2
2016_09_20 17:06 h1nds0
2016_09_20 17:06 h1nds1
2016_09_20 17:06 h1tw0
2016_09_20 17:06 h1tw1
2016_09_20 17:07 h1broadcast0
2016_09_20 23:16 h1fw0
2016_09_20 23:29 h1fw0

Maintenance day. Several rounds of PSL-ISS model and DAQ restarts. Addition of epics chans to SUSPROCPI. CALCS model change. FW1 powered down for cloning (not shown). Start of FW0 instability.

model restarts logged for Mon 19/Sep/2016
2016_09_19 02:25 h1nds0
2016_09_19 11:46 h1fw2
2016_09_19 11:49 h1fw2
2016_09_19 11:56 h1ascimc
2016_09_19 11:56 h1fw2
2016_09_19 11:58 h1fw2
2016_09_19 12:00 h1broadcast0
2016_09_19 12:00 h1dc0
2016_09_19 12:00 h1fw0
2016_09_19 12:00 h1fw1
2016_09_19 12:00 h1fw2
2016_09_19 12:00 h1nds0
2016_09_19 12:00 h1nds1
2016_09_19 12:00 h1tw1

unexpected restart of NDS0. FW2 cloning for Rolf. ASCIMC code change with DAQ restart.

I ran Hveto over the earlier lock, firstly from 01:00-06:00 UTC and then from 07:45-08:15 UTC to avoid TCS injections, here are the results pages:

https://ldas-jobs.ligo-wa.caltech.edu/~laura.nuttall/detchar/hveto/20160922/1158541217_1158559217/

https://ldas-jobs.ligo-wa.caltech.edu/~laura.nuttall/detchar/hveto/20160922/1158565517_1158540787/

Sadly there is nothing obvious standing out, and the signifiances of the round winners are not particularly high

sadly after several weeks of fault-free running we have had frame writer issues starting late Tuesday night. Only h1fw0 and h1fw1 are showing the problems, with h1fw2 stable. All three are running RCG2.3 code, the only difference is that fw2 has a local (non-QFS) disk. Some of the error messages from fw0 and fw1 suggest disk access issues.

One quick thing to try (which has helped in the past) is to power cycle the Solaris QFS-NFS servers. Under WP6179 we performed the following:

• reconfigured nds0,1 to serve h1fw1 frames
• power down h1fw0
• power cycle h1ldasgw0
• power up h1fw0
• reconfigure nds0,1 to server h1fw1 frames
• power down h1fw1
• power cycle h1ldasgw1
• while waiting for h1ldasgw1 to boot, h1fw0 restarted causing loss of frames
• power up h1fw1

We have noticed that some recent DAQ restarts appear to cause the Seismic BLRMS control room plot to lose its past data. The usual behaviour is to just show a gap while the DAQ was down (just a few minutes) and preserve all other times.

as a reminder that we have enhanced remote access controls in place during the hours of 8am to 4pm Mon-Fri, ssh sessions to lhocds.ligo-wa.caltech.edu now have a banner text display (see image). We have included the operator's phone number to call (we think this is already in the public domain).

Many thanks to Ryan for suggesting the use of the banner feature in SSHD.

We have made another round of modifications to the ISS second loop board to have a bit of more gain at 1kHz.

Boost 1 zero was increased by a factor of 2, BOOST 2 was added, and a bit of phase compensation for high frequency to allow us to push the UGF to 20kHz-ish (details of the mod will be attached to this entry).

In the attached, black is the measurement from yesterday at 50W, 7dB of VGA gain, boost on.

Blue is today with 13dB of VGA gain, first boost on.

Red is today with 13dB of VGA gain, second boost on.

All in all, the modifications bought us about 13dB at 1kHz.

If we really need more, we should be able to push the UGF even higher, but that needs some serious thinking.

After giving BRSX a day to cool off, I went to EX this morning to see if I could recover it. This required stopping the Beckhoff and recentering the damper assembly, the latter is not trivial. There are a few variables that need to be cleared in the Beckhoff, and they are kind of buried. But, the EX BRS is functional again, commissioners/operators can return the SEI_CONF to the WINDY state.

While I was there, I used a left over iLIGO hockey puck to damp the BRS down enough to re-engage the damping. I couldn't find Krishna's diagnostic plot, but the driftmon overview gives enough information, when the BRS is rung up enough to see on the driftmon (this plot is usually flat, it only goes sinusoidal if the BRS is rung up a lot). For future reference, you can do this by holding a mass above or below the beam, depending on the direction of the driftmon. Watch the driftmon signal and when it starts swinging in a positive direction (when it's at it's largest negative value of the sine wave) hold the mass above the right (-X) part of the horizontal part of the BRS vacuum can. Hold the mass below the can when the driftmon starts moving the other direction.

In order to combat the weirdness with the diode chiller temperature not reaching its desired set point
of 20 degC, I raised the set point to 21 degC.  This seems to have brought the chiller temperature
to ~19 degC.

    Trending the diode chiller temperature, one can see that there's an oscillation in the actual
temperature.  It might be to fool the system we ought to change the temperature set point to 22 degC.

From the trend data one can easily see the temperature oscillations that are apparent when one looks
at the chiller control panel.

Nutsinee, Kiwamu,

This is a belated log.

In this past Tuesday, we went to the HWS table and checked two things in order to study unexplained behavior seen by HWSY (29738). No major conclusion yet.

• We checked the spatial profile of the launching beam using a Thorlabs beam profiler.
  • We checked the beam up to the bottom periscope mirror. No obvious clipping was found.
• We checked the dependency of the returning beam position on the ITMY and CPY angles.
  • This test was unfinished because we ran out the maintenance period.
  • Nonetheless, according to a quick test, the beam(s) the HWSY camera receives seemed to be made of a reflection from ITMY and other reflection from CPY.
  • To be continued.

By the way, we (re-)found that a green beam coming down to the same HWSY path was clipped at its bottom part.

Computed coherences for a 10 minutes period starting at 05:00 UTC, September 22nd.

https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1158555617/

In the low frequency, there's coherence with MICH/SRCL (fig. 1), angular signals (fig. 2) and ITMY L2 control (fig. 3, not sure what is the control topology, maybe this is ok)

One very interesting thing: there is a significant broadband coherence with IMC_DOF_4_P (fig. 4) and with IMC-PWR_IN (fig. 5)

Lines at 57 Hz and 114 Hz are coherent with magnetometers.

We did a TCS tuning test at 50W starting at 6:56 UTC. The CO2X power was decreased from the nominal 400 mW to 0. During the test, we have monitored the frequency and intensity noise couplings to DARM by injecting broadband noise. I will analyze and post the results tomorrow, but it seems like that a small CO2X value is better fore laser noise couplings.

During the test, we tried to compensate for varing optical gain by changing the CAL-CS sensing gain setting. There was a period where we had a 80 Mpc range which was due to uncompensated change in the optical gain induced by the thermal transient. However, we believe that the range will be better with the fine tuned CO2s. Unfortunately, the laser tripped shortely after the test. We did not get a chance to examine the improvement.

We moved the IMC offsets, injecting lines in PIT and YAW on the IMC PZT around 400 Hz, and saw the improvement in the red trace on the second attachment. 

• We watched the lines in DARM and tried to move the IMC offsets to miminize the peaks (similar to what Robert and Kiwamu did in alog 29523). 
• We had tried to minize the jitter to intensity coupling in the IMC yesterday by watching the ISS second loop diodes, but were unable to do better than with no offsets in.  Watching DARM things were much more repeatable and stationary, which makes me think that whatever we are minimizing this way, it is not jitter to intensity coupling in the IMC.  We were suprised that moving the IMC alingment had a repeatable impact on the high frequency noise which is coherent with REFL.  We found that for IMC DOF1 P (which actuates on MC2 using a combination of the WFS signals) a good offset was 170 cnts.  We only tried DOF1 P and Y, so a more precise tunning could be done.  

Tonight we did a few more measurements to try to understand the jitter coupling:

• After powering up, I did some yaw injections on the IMC PZT while Jenne changed modulation depths, which had no impact on the measured coupling, suggesting that the jitter couples to DARM through the carrier field.  We made a reference injection at 01:13:26 Sept 22 2016 UTC, Jenne reduced the 9MHz modulation depth by 6dB (injection at 01:17:35), and then increased the 45 MHz modulation depth by 3dB (injection at 1:24:02).
• We later tried a test of changing the DARM offset, to see what impact it has on our noise, and while doing this did a few more excitations.  Changing the DARM offset had no impact on the measured coupling either, suggesting that jitter (edit: should not be) be coupling to the DC PDs on contrast defect light.
• The coupling for yaw did drop by almost 6dB, (without much change in shape) after the interferometer had been locked for several hours.  This could be consistent with the contrast defect or alingment changing as the interferometer thermalizes. We did not do a before/after thermalizing measurement for pit, but it might be interesting to try this tomorow. While the noise from 200Hz-1 kHz didn't improve dramatically with the thermal change, there are a few peaks that were smaller after the change, (compare blue to purple in the second attached screenshot)
• After moving the IMC P, the shape of the transfer frunction from IMC PZT yaw to DARM changed with the sharp features gone. 

Jenne, Sheila, Kiwamu, Terra, Lisa

We had another long lock at 50W tonight (7 hours so far), and we did several things (list below).

MICH feed forward retuning and IMC WFS offset adjustment had a clear impact on the noise; the IMC WFS offset tuning reduced several peaks in the noise between 500 Hz and 1kHz, and kept the noise above 4 kHz at the minimum. The noise floor is still significantly higher than it should be in the 500Hz-1kHz region, so there is clearly more to do there. Also, unclear at this point how stable these offsets actually are.

Here is the full list of things we did/tried:
Improved MICH subtraction - the best MICH FF gain with the current filters is -15.9 (-13.9 was loaded in the guardian, Jenne updated it) 
IMC WFS offset tuning: Sheila's entry will follow, bottom line is that the noise above 4 kHz is now much more stationary, and we reduced several peaks in the jitter noise between 500 Hz and 1 kHz;
we closed the POP beam diverter (it is still open in normal operation because we are using POPX, we just made a test by opening the ASC POPX loop for a few minutes, from Sep 22, 5.36 UTC to 5.41UTC); we don't think closing the beam diverter made a difference - we opened it again, once we transition to REFL we can close it permanently; 
 we explored different DARM offsets, no real impact on the noise; 
 we run A2L again, it does what is supposed to, but we noticed that the optimal tuning doesn't last long 
 we reduced the ITM ESD bias by a factor of 2 (Sep 22, 5.45  UTC - 5.48 UTC), we didn't see any change in the noise; 
 Jenne explored the dependence of DARM vs OMC alignment by adding offsets to the OMC ASC loops - nothing exciting 
 Terra turned off for a few minutes all the drives for the PIs - no effect on DARM 
 On going: Kiwamu is doing a thermal test by slightly changing the CO2 power - we want to see if we can minimize laser noise couplings this way.
  

Note:  we have a typically big 40.94 Hz ; we found past entries referring to the 40.93 Hz PR2 roll mode; we improved the band stop that it is already in the PR2 M2 actuation path by 40 dB at the exact frequency, but that didn't help; need to follow up on that, the line is big and it is modulated. 

We never had to worry about bounce and roll during the lock, so good job on the tuning  earlier in the afternoon! .

Attached is the OLTF in two configurations with 7dB VGA gain.

50W (actually 48W), AC coupling OFF, and boost ON (solid line)

50W (actually 48W), AC coupling ON, boost OFF (dashed).

UGF is about 9kHz with phase margin of 40 deg or so (boost ON) or 50 (boost OFF).

Boost buys us about 9dB more gain at 1kHz.

I asked Kiwamu to do an analog measurement up to higher frequency on the floor.

I've stepped all four ring heaters consecutively tonight by 4 W each to identify which test mass belongs to the new 17783 Hz/47.7 kHz PI mode (alogs 29820 and 29838). The shift in frequencies of the test masses is dominated by a change in the Young's modulus which we can alter via the ring heater power; by stepping each ring heater and finding which causes a larger relative frequency shift of the mode in question, we can identify which test mass the mode is from.  See T1600080 and LLO alog 18002 for more info. All power changes below were applied to both top and bottom ring heater. All times UTC.

ETMX: 0.75 --> 2.75 @ 9:29 --> 0.75 @ 9:48

ETMY: 0 --> 2 @ 9:49 --> 0 @ 10:08

ITMX: 0.25 --> 2.25 @ 10:08 --> 0.25 @ 10:29

ITMY: 1.25 --> 3.25 @ 10:31 --> 1.25 @ 10:41

Note we just lost lock around 10:42, probably due to these ITM steps.